Pilot operated control device



May 5, 1964 N. E. ANDERSON 3,132,235

PILOT OPERATED CONTROL DEVICE NELSON E. ANDERSON ATTORNEYS May 5, 1964 Y N. E. ANDERSON 3,132,235

PILOT OPERATEO CONTROL DEVICE Original Filed April 28, 1958 Y 2 Sheets-Shea?I 2 SWITCH 2O ADJUSTABLY POSITBONED ON VALVE BODY AND PERMITS OVERTRAVEL. OF PLUNGER I9.

l FIG. 3

l INVENTOR.

NELSON E. ANDERSON YZEMW ATTOR N EYS lapplication Serial No. 731,317

My invention relates to pilot operated controldevices and more specifically tofsuch devices which'are of particular utility in protecting and controlling the operation of gas shieldedarc Welding apparatus.

This application is a continuation of my'copending yled April 28, 1958, now abandoned.

Iny gasshielded arc welding, a suitable gas` is .supplied United States Patent n times added so that Water pressure drops of short duration will not cause shut down of the apparatus.

\It is thus obvious that-gas-arcl welding apparatusgenerally requires certain control elements to protect against inadequate cooling water flow and to provide pre-weld and post-weld gas shielding of the electrode yand the work as part of each welding operation which may be of considerable duration as when making a line weld or of short duration as, when making tack or spot welds. These control elements comprise time delay devices, a pressure sensitive switch, and solenoid 'operated valves or their equivalents. i

vInexpensive thermal-type ltime-delay ydevices are exf cellentfor use witha pressure switch tor prevent `outage due konly to momentary loss of water pressure. In fact this type is preferable sincefit is an integratingL device,

simulates' the heating of the yapparatus due to the lack about the electrode and the molten portions of the work and cooling Water is usuallyksupplied tofthe electrode holder and its connections in the Welding torch as well as about the Welding cable'connected to the `torch in order to prevent destructive heating of these parts by reasonl of the high cuirent densities employed therein in order to yreducetheir weight and thus the fatigue imposed on the operator who must handle them when performing aweld ing operation. Furthermore, the torch gas nozzle which surrounds the arcingtip of the electrode in the torch is directly subjected tothe heat of the welding arcand Water cooling of this part is desirable in order to increase its operative usefulness. f

In gas-arc welding it is generally the practice to initiate the flow of gas before the welding arc is established and to maintain this gas flow for a period of time after the welding arc has been interrupted at the end of the i welding operation. The pre-welded gas iiow purges the.

gas passages about the electrode and thework and insures that the welding arc operates in the desired atmosphere which will also serve to protect the electrode from oxidation byy the surrounding air, The post-Weld gas flow also protects the hot` electrode from oxidation by the air and permits the molten weld metal to ycool and solid ify while being protected from oxidation by the surroundmg a1r. y f

Gas-arc Welding apparatus may embody either consumable electrodes that are fed to they arc as they are fused and depositedy in the Weld or non-consumable electrodes, such as tungsten, which deposit no metal in the f weld. Tungsten electrodes are readily oxidized when the Welding operation is performedk in air and such oxidation yis prevented by pre-Weld and post-Weld shielding the electrode with a suitable gas. This gas shielding also insures the desired operating characteristics'of the arc. The shielding gases commonly employed are argon, helium and mixtures thereof to which at timeswadditions yof oxygen, carbon dioxide or some other gas yare made to secure certain desirable results. These gases are expensive and consequently are supplied only when needed during the welding operation. This is equally true when a less expensive shielding gas,such as carbon dioxide, ris used in performing vthe welding operation. l

Provision must also be made to prohibit the use of the apparatus for welding if` an adequate flow of cooling Water therein is not obtained. Any device that protects against inadequate water flow'through the apparatusy is quite expensive and it hasy been deemed satisfactory to provide a pressure sensitive device that will not allow operation of the apparatus if the water pressure fallsj be-V of water, and would shut down the apparatus in the event .that the pressure drops become frequent.' kThe slow re,`

set characteristics of' thermal kdelay devices make them unsuitable for gas pre-weld and post-Weld shielding purposes.y High timing accuracy is notrequired for preweld and post-weld shielding and it is possible to buy tirne-delays relays of suiiicient accuracy at low prices but these relays are not reliable4 in that they often fail to function at all: Consequently in the past it has been kfound necessary to use expensive pneumatic timers in order to obtain kreliable timing operations.` y

Itis an object of my invention to provide at reduced cost a control device which will protect gas-arc ywelding apparatus against inadequate and provide for such apparatus means for obtaining preweld and post-weld gas shielding operations fof different and adjustable time periods. u u

It is also an object of my invention to provide a device t. embodying avalve and ra switch which are sequentially operatedfby ya flexible chamber embodying a diaphragm or kbellows which is movable against a biasing means by fluid under pressure which is supplied to and exhausted y,

rof a gas pressurev regulator such as may be used for controlling the flow of gas during an arc welding operation,

so that full advantage may be taken of the low cost yof u mass producing the parts of these devices and of the convenience of stocking them for replacement purposes. y

Further objects'of my invention will become apparent from the following description of one embodimentthereof. In apparatus embodying my invention a lexible diaphragm acts through a thrust pin on the movable valve element of a valve. This valve element is biased to a position in which it closes the passage through the body yportion n of ,the valve by a spring which acts on a plunger and forces one end thereof against the valve element on the l side thereof which is opposite its 'side which is engaged kby the thrust pin. The -other end of the plunger projects from lthefbody portion of the Valve and operates an electric switch adjustably positioned relative thereto for er1- gagernents yby the plunger upon'a predetermined movement thereof against the biasing action of the plunger spring. The diaphragmn forms a movable wall portionL y Patented Mayif, v1964 cooling water f i'low' i nected by means including two parallel passages with a source of iiuid whose supply pressure may be subject to change. An adjustable throttle valve is provided in one of these parallel passages for controlling the rate of flow of fluid into and out of the chamber in the casing and a check valve is provided in the other of these parallel passages to permit the flow of fluid into a chamber in the casing and to prohibit its flow therefrom. Thus fluid can be supplied to the chamber in the casing at a more rapid rate than it can be exhausted therefrom.

With this organization of parts, when the fluid pressure in the casing chamber moves the flexible diaphragm against the biasing force of the plunger spring, the valve is opened and the plunger moves toward the switch to actuate it after a predetermined travel, the time for which is determined by the rate at which fluid is supplied to the chamber through both of the parallel passages leading thereto. Conversely if the pressure of the plunger spring overcomes the water pressure on the diaphragm, the plunger moves in the reverse direction to open the switch and thereafter to close the valve after a time delay determined by the flow of fluid through only one of the parallel passages. The time intervals between operation of the valve and operation of the switch and their reverse perations are different by reason of the operation of the check valve in one of the parallel passages to the chamber in the casing. Suitable overtravel of the plunger relative to the switch is provided .so Vthat momentary loss of fluid pressure in the casing chamber will not cause operation of the switch. In this way it provides the protection heretofore obtained from thermal-type time-delay devices associated with a pressure switch to prevent outage due only to momentary loss of cooling water pressure. It consequently acts as an integrating device responsive to the heating of the apparatus due to lack of adequate water cooling and will only open the switch to shut down the apparatus if drops below a desired water pressure suitable for yadequate cooling become too frequent.

This pilot operated control device may be used to secure the desired operation of a gasaarc welding apparatus by connecting the pressure chamber in its casing through the parallel passages thereto to the cooling water supply, by connecting the valve thereof inthe gas supply line of the lwelding apparatus, and by connecting the switch thereof in a circuit which operates a contactor which controls the supply of Welding current to the electrode of the apparatus and to the work. The welding operation is initiated by opening a valve in the cooling water line to supply cooling water to the welding apparatus and to apply its pressure to the control device, and the welding operation is terminated by closing this valve. This valve in the Water line may be a solenoid valve whose operation is controlled by .a push button mounted on the welding torch and having contacts in circuit with the solenoid winding of the valve. Then, with a proper adjustment of the device, if the cooling water supply pressure is suflicient to provide suitable cooling of the apparatus, it supplies to the diaphragm of the device a pressure greater than the spring pressure applied to the plunger of the device, the gas valve is opened to supply gas to and about the electrode and the Work and, after a delay period, the switch is operated to complete the welding circuit to the electrode and the Work and thus permit striking the welding` are to initiate the welding operation. Thereafter, as pointed out above, if the supply pressure of the cooling water falls for -an integrated time period to a value which would provide inadequate cooling of the apparatus, the spring biased plunger will move in a reverse direction opening the switch to interrupt the supply of welding current to the arc and, after a delay period, to close the gas valve and prevent waste of the shielding gas.

My invention will be better understood by considering in detail the construction of one embodiment thereof and its use `as part of a gas-arc welding apparatus `as shown in the accompanying drawings wherein:

FIG. 1 shows my pilot operated control device as part of a gas-arc welding apparatus,

FIG. 2 is a cross-sectional View of this device showing the working parts thereof, and

FTG. 3 is a cross-sectional view showing the construction of the adjustable throttle valve forming part of the device.

In FIG. 1 my control device l1 is connected to control the flow of shielding gas through pipes 2 and 3 from a gas cylinder 4 to `a manual gas-arc welding torch 5 having a handle 6 and a head 7. The rate of gas flow is determined iby a pressure regulator 8 and indicated by a direct reading owmeter 9. The gas supplied to torch 5 is discharged through its nozzle 1@ about a tungsten electrode 11 supported in an electrode holder forming part of the torch. Cooling Water is supplied to the torch from a supply pipe 12 through a solenoid operated valve 113, which is biased to its closed position, a pipe 14, an adjustable throttle valve 1S, and `a pipe 16 and is exhausted from the torch through a pipe 17. A pipe connection 18 applies the pressure of the water supply to the control device 1.

Control device 1 has a movable plunger 19 which engages and operates a switch Ztl. This switch is adjustably positioned relative to the body portion of the control device on which it may be mounted as a part thereof and its blades are suciently deformable so as to permit overtravel of the plunger after it has closed lthe switch contacts. Switch I20 is connected in circuit with conductors 23 and 24, contacts 25 of a relay 26, a conductor 2.7, the operating lwinding 28 of a contactor Z9, and a conductor 31) across supply conductors 21, 22.

The operating winding 31 of relay 26 is connected across supply conductors 21, 22 through a conductor 32, contacts 33 of a push button switch 34, and conductors 35, 36 and 37. The operating winding 38 of the solenoid Water valve 13 is connected across :supply conductors 21, 22 through conductor 32, contacts 33 of push button switch 34, and conductors 35 and 35. Contacts 5S of contactor 2.9 connects the output circuit of the Welder 39 to the electrode 11 of the welding torch and to the work 40 through conductors 41, 42 and 43, the secondary winding 4dof a coupling transformer 45, and a conductor 46. The -welder 39 is energized `from the supply `conductors 21, 22 through conductors 47 and 4S, a disconnect switch 49 and a conductor S0. Contacts S1 of contactor 29 connects the input circuit of a high frequency oscillator 52 across the supply conductors 21, 22 through conductors 30, 53 and 5d, Ia disconnect switch 55, and a conductor 56. The output circuit of the oscillator 52 is connected across the primary winding 57 of the coupling transformer 4S. A high frequency bypass capacitor 45 is connected across the welding conductors 46 and 42 so that for arc starting and arestabilization the high frequency of the oscillator can be supplied across electrode 11 and Work 40 fwithout passing through the Welder.

To prepare the system of FIG. 1 for welding, the operator opens the valve on cylinder 4 to supply shielding gas through pipe 2 to the gas valve in device 1 which is biased to its closed position and consequently prevents the flow of gas through pipe 3 to the welding torch S. He will also close disconnect switches 49 and 55 to prepare for the use of Welder 39 and oscillator 52. Thereafter he may initiate a welding operation by closing push button switch 34.

Closure of switch 34 will energize the operating winding 38 of solenoid valve 13 and the operating winding 31 of relay 26. Energization of winding 38 opens valve 13 from its biased closed position and supplies cooling water through pipe 14, throttle valve 15 and pipe 16 to the welding torch from which it is exhausted through pipe 17. At the same time water pressure is applied to device 1 lil through pipe 18 and it operatesto yopenits gas valve and permit the 'flow of shielding gas fromcylinder 4 through pipes 2 and 3 to the Welding torch 5 vfrom which it is disitscontacts 58 and 51. The closure of its contacts 58y connects the output circuit of Welder 39 across the electrode 11 of torch-5 and the work 40 through the secondary winding 44 of the coupling transformer 45.

The closure of its contacts 51 completes the input circuit to high frequency oscillator 52 which. consequentlyoperatcs to supply high frequency voltage and current to the primary winding 57 of coupling transformer 45. vThis energization of the coupling transformer 45 applies the high frequency of the oscillator across the electrode 11 of the torch l and the Work 4t) tol enablev the operator to strike the Welding arc Without'touching the electrode tothe work and thereafter to maintain its operation with arc Welding current supplied from Welder 39. y e

As pointed out above, device 1 is so constructed that there is suitable overtravel of plunger 19afte'r it operates switch 20. This is employed to take care of momentary drops in cooling water pressure so that shut down will not occur due to those momentary pressure drops which are not'frequent enough to produce destructive heating of the welding apparatus. lf during the welding operation the escaping by the plunger and through its holder.

and makes a threaded engagement with a socket 73 formed in the valve body. The closingforce exerted on valve member 6) by plunger y19 is madeadjustable by means of a screw 74 which makes a threaded engagement with the outer end Wall of the spring cavity in holder 72 and acts against one `end of spring 71. Ther other end of this spring engages and acts on a collar on the inner end of plunger 19 and between this collar and an adjacent collar spacedtherefrom there is an O ring seal 76 to prevent gas A packing washer 75 between shouldered portions of holder 72 and valve body 61 also prevents the escape of gas from 'the valve body at the joint between these parts. Adjusting screw 74 has a longitudinal bearing through which i the inner end of plunger 19. This thrust pin is actuated byra flexible diaphragm 78 which engages its other end` through a thrust plate 79 forming part of the diaphragm structure. y

` Diaphragm 7S, constitutes a movable wall member which closes a Wall opening in a casing Si) forming part of the pilot mechanism of my device. A peripheral portion ,of diaphragm 7S is held between casing il() and the valve cooling water pressure drops to a value less than that for which the device 1 is sct, it Will, after a delay period suitable to take care of momentary pressure drops, open switch 20 and de-energize contactor 29 which will open its contacts to deenergize oscillator 52 and disconnectvvelder A39 from the Welding circuit. After the post-Weld delay period for which device 1 is set, the flow of gas to the torch will also be interrupted.y y.

The operatorcan discontinue the welding operation by opening push button switch iltwhich will de-energize relay 26 and solenoid valve 13. De-energization of solcnoid valve 13 will permit it to close and thus interrupt the iiowof cooling water to the welding torch. This removal of Water pressure from deviceml will cause it to close its gas valve after a post-weld time delay period and' thus interrupt the flow of shielding gas to the torch. The deenergization of relay 26 de-energizes contactor 29 which l disconnects Welder 39 from the Welding circuit and debody. The valve member dit is located in and guided by a bore 63 which is in the valve body and located opposite ythe seat member S9. The valve passage extends between inlet vsocket 64 and outlet socket 65 and comprises bores 66, 63, 68 and 69 formed in the valve body and bores 7i? r'formed in the projecting endportion of plug 62 which is located in bore dS and spaced from the side Wall thereof.

kInlet and outlet sockets 64 and 65 are threaded to provide connections for fittings on kthe ends of gas pipes 2 and 3 previously described as forming part'of the apparatus of FIG. l.

The'inner endof plunger 19 of device 1 engages Valve element and is forced there against by spring 71 which biases' it to close the port in seat member 59. Plunger 19 and its biasingspring 73kty are located in the longitudinal cavity of a holder 72 one end of which is reduced in size' body by a coupling nut 81. kA back-up ringSZ supported y* on the valve body and positioned to engage a peripheral 'portion of thediaphragm which is 'exteriorto the cavity .in casingtl limits the bellowing thereofy in its movement yaway from the casing.

Casing liti is provided with a head d3 having parallel pasages 84 and Siek therein through' which the How of Water from pipe 1S 'into and out of the chamber in the casing is controlled. An yadjustable throttle valve 86 in 84 and 85 therein and forms aconnectionfor a tting @attached to the end of water pressure pipe 18. This tting is provided withailter 9d to keep dirt out of the orifices of valves Scand 87. Filter clogging is unlikely since in this area the same water surges inand out of the device during the operation thereof.

A screw 915 whose head structure forms a seal in a short countersunk entrance to the threads therefore in the valve vbody is provided to ventair from the chamber in casing Si?. Backing the screw out a half turn will allow suiicient leakage past the threads to vent the air, after which screw 91 is tightened. y

The' body portion 61 of my device is a modification yof a like part of a pressure regulator and will consequentiy have a passage from the low pressure or'outlet side of the valve to the chamber which is on the other side of diaphragm 7S from that of the water pressure chamberincasing When the gas vvalve is open this gas pressure is low, being of the order of two pounds per Check valve @7 in passage Siof the casing head com-r prises a length of flexible tubing making a slight interference tit in the exit hole of throttle Valve *86.y This hole forms partof passage and extends into the casing chamber. The flexible tubing is deformable relatively to the wall of the hole in which it is located when the water pressure in pipe 1S is slightly greater than the water pressure in casing 80 to allow the supply of water through passage S5 into the casing. When the water pressure in the casing is greater than that in pipe 13, ow of water from the casing through passage 85 is prevented by the sealing action between the wall surface of the length of iiexible tubing and the wall surface of the hole in which it is located. Any flow of fluid from the chamber in casing 80 must consequently be through throttle valve 86.

The physical structure of the throttle valve is shown in FIG. 3. It comprises internal and external screw members of circular cross section interposed in passage 84 and adapted to make a threaded engagement with one another along portions thereof wherein lengths of thread of each of the members have been fully formed and are of equal and complementary depth and adjacent which are other portions of said members wherein the top of the thread of one member is progressively spaced along the length thereof by an increased amount from the bottom of the groove between the thread on the other of said members to form a tapered passage between the threads. The internally threaded member has an exit hole therein to that portion thereof having a fully formed length of thread and it is through this hole that water passes into and out of the chamber in casing 80 under the control imposed by the relative adjustment of the screw members of the throttle valve. The above described adjustable orifice through the throttle valve may be constructed by tapping the internal thread with a standard starting tap, not allowing any cutting at the bottom of the thread hole, and by machining off the ends of the threads of the externally threaded member to the same taper as the end of the starting tap. Sufficient full threads are left at either side of the exit hole to keep the externally threaded screw member concentric with the bore of the internal screw member. With this arrangement a very smooth tiow control is obtained at the equivalent of a small orifice and the construction described has the advantage of being easily cleaned by merely tightening and loosening the threads a few times.

Handle 88 on the stem of the external screw member of the throttle valve constitutes means for rotating one of the screw members relatively to the other to move them longitudinally of one another and thereby vary the position of the tapered passageway between the threads of these members relative to the exit hole in one of the members. An O ring seal 92 between spaced collars on the stem of the externally threaded screw member engages the wall surface of a cavity extending beyond the threaded portion of the internal screw member to prevent leakage of water from the valve.

In View of the detailed description above given of the structure of the pilot operated control device of my invention, its operation is apparent in View of the previously given general description thereof and what has been previously stated relative thereto in describing the organization and operation of the gas-arc welding system of FIG. 1 of which it forms a part. The following is a recommended procedure for adjusting the device. With switch 24B positioned relative to plunger 19 for a minimum pre-weld gas'flow time, spring 71 is compressed by adjusting screw 74 to provide for the desired cut-off water pressure. Throttle valve 86 is then adjusted for the post-weld gas shielding time and then switch 20 is adjusted relative to plunger 19 for the desired pre-weld gas flow time. If this time is long and the water pressure is low, it may be necessary to repeat these steps. As shown in FIG. 2 a throttle valve 85 may be placed in passage 85 so that a change of the pre-weld gas flow time may be obtained by controlling the rate of water flow through passage S5. Such an adjustment will not affect the minimum pressure setting determined by the compression of plunger spring 71. Alternately some well known linkage might be employed for acting on plunger spring 71 to permit a wide variation in the pre-weld gas ow time adjustment without affecting the minimum pressure setting for cut-out due to low water pressure. The device will operate best with fifteen pounds or more pressure differential between the supply pressure and the pressure cut-out setting. Preferably full line pressure is applied directly to the device by having the throttling valve for controlling the flow of water to the welding torch located down stream of the device as shown in FIG. 1. This will eliminate the time necessary to build up back pressure in the exible hoses of the welding equipment which would otherwise cause a delay between the initiation of water flow and gas ow. It is of course understood that pipes 3, 16 and 17 of FIG. 1, which extend from the rear end of handle 6 of the welding torch 5 will be made flexible in order to provide the welding operator with that freedom of manipulation which he requires when performing a welding operation.

The water pressure sensitive device above described may be converted into a ow sensitive device by adding a second diaphragm and a restricting orice in the water line in accordance with the disclosure in Patent 2,517,739, Joseph M. Tyner and myself, August 8, 1950. It is contemplated that operation with such a modification will produce better performance at a water pressure close to the minimum required, but the pressure spring would need be much weaker and thus require a very good valve seat and low friction in the plunger seal.

These and other modifications will occur to those skilled in the art in view of the above description of the structure and use of my pilot operated control device. 'It is of course apparent that the device may be used for purposes other than sequencing the operation of a gas-arc welding apparatus. For example, it could be adapted to perform the ease-on function for thermo-chemical piercing. It could also be used to control the gas flow in gas shielded arc welding by using the pressure of the gas to control operation of the device.

'Ihus, while I have fully described but one modification of my invention, other modifications and adaptations thereof in addition to those suggested will readily occur to those skilled in the art. It is consequently my intention to cover by the appended claims all such modifications and adaptations of my invention which do not constitute a departure from the spirit and scope thereof.

What I claim is:

1. In a gas-arc system adapted to be supplied with shielding gas and electric welding current, and comprising a gas-arc torch, a valve interposed in the conduit through which said shielding gas is supplied to said torch, and a switch interposed in a circuit controlling the flow of electric welding current to said torch: apparatus for the sequential control of the flow of said shielding gas relative to welding current for proper pre-weld and post-weld gas flow, rcomprising a control fluid chamber, a control element associated with said control huid chamber which is displaced in a forward direction upon admission of control fluid under pressure to said control fluid chamber and which is displaced in the reverse ldirection upon discharge of control fluid from said control fluid chamber, means responsive to the displacement of said control element to operate said valve and said switch in pre-determined sequence in a forward direction and in a reverse sequence in the reverse direction and metering rate means for controlling at differing rates the respective admission and discharge of control fluid to and from said chamber, to thereby cause a time delay period of a different duration as between operation of said valve and operation of said switch in that order in their forward direction, and operation of said switch and operation of said valve in that order in the reverse direction.

2. In a gas-arc system adapted to be supplied with shielding gas and electric welding current and comprising a gas-arc torch, and a switch interposed in a circuit controlling the flow of electricwelding current to said torch: apparatus [for the` sequential controlof the flow of said shielding gas relative to welding current for proper preweldy and post-weld gas flow, comprising a control fluid chamber, a control element associated with said control fluid chamber which is displaced in a given direction upon admission of control fluid under pressure to said control fluid chamber andwhich is displaced in the'opposite direction upon discharge of rcontrol fluidfrom said control flui-d cham-bena valve interposed in the conduitfthrough which said shielding ygas is supplied to said'torch, means responsive to the displacement of said control element to operate said valve and said switch in pre-determined sequence -both in a forward direction and in a reverse direction, and metering rate means lfor controlling lat differing rates the respective admission and discharge of ycontrol fluid to and from said chamber, to thereby cause atime delay period of a 'dierenttduration as between operation of said valve and operation of said switch in that order in their forward direction, and operation of said i' switch and koperation of said valve in that order in the reverse'direction, said metering rate means effectively restricting the aforesaid admission of4 control kfluid so as to afford a pre-determined delay interval between the preweldoperation of said gas flowand the operation of welding currentilow, and more greatly restricting the aforesaid discharge of control fluid so as vtoafford a longer interval between termination of; the welding current `flow and termination of the post-weld operation of the shielding gas flow. v f

3. In a gas-arc system adapted to be supplied with shielding gas and', electric currentV and comprising a gas-arc torch, and a valve interposed'in the conduit through'which said shielding gas isy supplied to said torch: apparatus for the sequential control of the flow of said shielding gas relative to electric current for proper pre-weld and postweld-gas flow, comprising a switch interposed in a circuit controlling the flow Vof electric current to said torch, a ycontrol fluid chamber, a control element associated with said control fluid chamber which is displaced in a `given in W . with said fluid, chamber which is displaced in a forward v to said fluid chamber and which is displacedin a reverse directionupon admission of control fluid under pressure A* to saidcontrol fluid chamber 'and whichk is displaced'in from said control'fluid chamber, means responsive to the displacement of said control element to operate said valve and said switch in pre-determined sequence both in a forward'direction and in a reverse direction, and metering rate means for controllingat differing rates the respective admission and discharge of ycontrol fluid to and from said chamber, to thereby cause a time delay period of a different duration as between operation of ysaid valve 'and operation of said switch in that'order in their forward direction, and operation of said switch and operation of said valve in that orde-r in the reverse direction, said metering rate means effectively restricting the aforesaid discharge of controlfluid so as to afford a pre-determined long interval ifordelaying termination of the operation of both said kswitch and said current flow insaid reverse di- 4rection, and another pre-determined long interval bet-Ween the termination of the current flow and the termination of the post-weld operation of the shielding vgas flow.y

4. in a gas-.arc system comprising a coolant-cooledy torch Whichgis adapted to be supplied with shielding gas and yelectricy current, a shielding gas conduit connected to said torch through which shielding gas is supplied thereto, and akcoolant conduit connected to saidftorch through which coolant issupplied thereto: improved' controlling apparatus comprising a switch interposed in a circuit controlling the flow of elect-ric ycurrent to said torch, and a single control unit having plural components consolidated therein for the sequential control of the flow of said shielding'gas relative to said electric current flow for proper pre-weld and post-weld gas flow, and consisting of a control fluid chamber, a control element associated `direction upon discharge of control fluid from said fluid chamber, a gas valve interposed in said shielding gas conduit, means responsive to the displacement of said control elementto operate the gas ,valve and said switch in predetermined sequence both in a forward direction and in a reverse direction, means connected to said coolant conduit and effective for supplying said coolant under pressure as a controly fluid'to.` the fluid chamber, and a metering y rate control for controllingnat differing rates the respective admission and discharge of control fluid to and from said chamber, to thereby cause a time delay period'of a different duration as lbetween operation ofthe gas valve and operation offsaid switch and operationof said valve in that order in the reverse direction, said metering rate control comprising passage means in said coolant-conduitconnected means, the number of said passage means consisting of at least one restricted passage in number, and having restriction adjusting means therein for adjustably restricting the kflow of control fluid therethrough into said fluid chamber, to adjust the'pre-weld time delay of said switch'to a period sufficient for proper prior purge-flow of said shielding gas. n

5. In a gas-arc system adapted to bey supplied with shielding gas and electric welding current,l and cornprising a gas-arc torch, a shielding gas conduit through which shielding .gas is supplied to said torch, a cooling lluidconduit connected to said torch ythrough which coolinig fluid is supplied thereto, and a switch interposed in a circuit controlling the flow of electric welding current to said torch: a single control devicey unit having plural components consolidated therein for `the sequential controlof ther flow of said shielding gas relative to welding current for proper pre-weld and post-weld gas flow, and consist- Y control the flow of gas supplied to. thek torch, meansresponsive to the displacement of said control element to operatesaid gas valve and said switchin pre-determined sequence both in a forward direction and in a reverse direction, rneans for supplying said cooling fluid from said cooling fluid conduit to the fluid chamber, and plural metering rate means for controlling at differing rates the respec- 'tive'admission land discharge of coolingffluid to and from said chamber, to therebycause a time delay period of a dierentldnration as between operationof said gas rvalve and operation of said switch in that order in their forward directionand operation' of saidswitch and operation of said gas valve in that order in the reverse direction.

6. Single control device unit in a system in accordance with claim 5,*wherein said plural metering rate `means, consists of first and second parallel passages in said means for supplying ksaid cooling fluid to the fluid chamber, ad'- justable restrictive means in said first passage for adjustably controlling the rate at which cooling fluid passes S. Apparatus according to claim 7 in which at least n one ofy said parallel passages includes an adjustable flow control valve. y f

9. Apparatus comprising a valve having a body portion with a passage therethrough and a valve element movable relatively to said body portion 'for variously obstructing said passage, a casing, a exible diaphragm, means for clamping the periphery of said diaphragm between said casing and the bod-y portion of said valve to form a pressure chamber in said casing, a thrust pin mounted for lengthwise movement in saidvalve body and positioned thereby in contact with and intermediate said diaphragm and said )valve member, a plunger, a holder for guiding said plunger lengthwise thereof and from which one end of said plunger projects, means in said yholder for biasing said plunger in the direction of its said projecting end, means in said holder for adjusting the force of said biasing means, means `for mounting sai-d holder in said valve body with said projecting end of said plunger in engagement with said valve member against which it acts by its said biasing means to resist the force applied to said valve member by said diaphragm acting through said thrust pin, means including parallel passages for connecting said pressure chamber in said casing with a source of tluid whose supply pressure is subject to change, means in one of said parallel passages of said connecting means for adjustably controlling the rate at which huid passes through said one parallel passage into and out of said pressure chamber in said casing, and means in the other of said parallel passages of said connecting means for permitting Athe flow of iluid through said other parallel passage into said pressure chamber in said casing and prohibiting the flow of fluid therefrom.

l0. Apparatus comprising a valve having a ported seat member, a movable spherical ball valve member and a body portion with a passage therethrough which is variously obstructed by the relative positions of said members therein, a casing, a llexible diaphragm, means for clamping the periphery of said diaphragm between said casing and the body portion of said valve to form a pressure chamber in said casing, a plug engaging said valve body and holding said seat member intermediate the ends of said passage in said valve body and opposite the end of a bore in said body member which guides said ball valve member relative to the port in said member, a thrust pin extending through said plug and guided thereby into contact with and intermedate said diaphragm and said ball valve member with one end thereof extending through the port in said seat member, a plunger mounted for lengthwise movement in said valve body with one end thereof opposite said ball valve member, means for biasing said plunger into engagement with said ball valve member and against a force applied thereto by said diaphragm acting through said thrust pin, means for adjusting the force of said biasing means, means including parallel passages for connecting said pressure chamber in said casing with a source of fluid whose supply pressure is subject to change, means in one of said parallel passages of said connecting means for adjustably controlling the rate at which fluid passes through said one parallel passage into and out of said pressure chamber in said casing, and means in the other of said parallel passages of said connecting means for permitting the ow of iiuid through said other parallel passage into said pressure chamber in said casing and prohibiting the ilow of said fluid therefrom.

11. Apparatus comprising a valve having a body portion with a passage therethrough and a Valve element movable relatively to said body portion for variously obstructing said passage, a casing, a exible diaphragm, means for clamping the periphery of said diaphragm between said casing and the body portion of said valve to form a pressure chamber in said casing, means for limiting the bellowing of said diaphragm in its movement away from said casing, said means including a back-up washer supported on said valve body and positioned to engage a peripheral portion of said diaphragm which is exterior to said casing, a thrust pin mounted for lengthwise movement in said valve body and positioned thereby in conl2 tact with and intermediate sind diaphragm and said valve member, a plunger, a holder for guiding said plunger lengthwise thereof and from which one end of said plunger projects, means in said holder for biasing said plunger in the direction of its said projecting end, means in said holder for adjusting the force of said biasing means, means for mounting said holder in said valve body with said projecting end of said plunger in engagement with said valve member against which it acts by its said biasing means to resist the force applied to said valve member by said diaphragm acting through said thrust pin, means including parallel passages for connecting such pressure chamber in said casing with a source of fluid whose supply pressure is subject to change, means in one of said parallel passages of said connecting means for adjustably controlling the rate at which fluid passes through said one parallel passage into and out of said pressure chamber in said casing, and means in the other of said parallel passages of said connecting means for permitting the ilow of fluid through said other parallel passage into said pressure chamber in said casing and prohibiting the ilow of fluid therefrom.

l2. Apparatus comprising a valve having a ported seat member, a movable spherical ball valve member and a body portion with a passage therethrough which is variously obstructed by the relative positions of said members therein, a casing, a flexible diaphragm, means for clamping the periphery of said diaphragm between said casing and the body portion of said valve to form a pressure chamber in said casing, means for limiting the bellowing of said diaphragm in its movement away from said casing, said means including a back-up washer supported on said valve body and positioned to engage a peripheral portion of said diaphragm which is exterior to said casing, a plug engaging said valve body and holding said seat member intermediate the ends of said passage in said valve body and opposite the end of a bore in said body member which guides said ball valve member relative to the port in said seat member, a thrust pin extending through said plug and guided thereby into Contact with and intermediate said diaphragm and said ball valve member with one end thereof extending through the port in ksaid seat member, a plunger mounted for lengthwise movement in said valve body with one end thereof opposite said ball valve member, means for biasing said plunger into engagement with said ball valve member and against a force applied thereto by said diaphragm acting through said thrust pin, means for adjusting the force of said biasing means, means including first and second parallel passages for connecting said pressure chamber in said casing with a source of fluid whose supply pressure is subject to change, means in one of said parallel passages of said connecting means for adjustably controlling the rate at which iiuid passes through said one parallel passage into and out of said pressure chamber in said casing, and means in the other of said parallel passages of said connecting means for permitting the flow of fluid through said other parallel passage into said pressure chamber in said casing and prohibiting the ow of said fluid therefrom.

13. Apparatus comprising a valve having a body portion with a passage therethrough and a valve element movable relatively to said body portion for variously obstructing said passage, a casing, a flexible diaphragm, means for clamping the periphery of said diaphragm between said casing and the body portion of said valve to form a pressure chamber in said casing, a thrust pin mounted for lengthwise movement in the body portion of said valve and positioned thereby in contact with and intermediate said diaphragm and said valve element, a spring biased plunger mounted in the body portion of said valve and having one end projecting therefrom and its other end in biased engagement with the side of said valve element which is opposite its side engaged by said thrust pin, means including parallel passages for connect- 13 ing said pressure chamber in said casing with a source of luid whose supply pressure is subject to change, means ,in one of said yparallel passages of saidconnecting means for adjustably controlling the rate at which fluid passes through'said one parallelpassage into and outk of said pressure chamber inesaid casing, and means in the other of said parallel passages of said connecting meansfor permitting the flow of Huid through said other parallel passage into saidpressure chamber in said casing an prohibiting the flow of iiuid therefrom. y f

14. Apparatus comprising a valve having a body portion with a passage `therethrough and a valve element movable relatively to said body portion `for variously obstructing said passage', a casing, a exible diaphragm,

means for clamping the periphery of said diaphragmy between said casing and the body portion of said valve yto form a pressure chamber in said casing,la thrust pin mounted for lengthwise movement in the'bodyportionof said kvalve and positioned thereby in contact with and intermediate said diaphragm andisaid valve element, a plunger, aVholder fory guiding said plunger Vlengthwise thereof and Lfrom which they ends of said plunger project,

`means for mounting said holder in `the body portion of said valve with one end of said plunger' opposite the side of said valve element Whichris opposite its side engaged by said thrust pin and with its other end projecting from `the'body portion of said valve, means in said holder for biasingfsaid plunger into 'engagement with said valve yelement to resist ythe force applied thereto by said diaphragm acting through' said thrustv pin, means inlsaid holder for adjusting vthe force of said -biasingrneana means including parallel passages for connecting said pressure chamber in said casing with a source of fluid whose v krsupply pressure is subject to change, means in'one ofpsaid t 'la member, a movable spherical ball valve member and a body portion with ya passage therethrough which is variouslyobstructed by the relative positions of said members therein,` a casing, a flexible diaphragm, means for clamping the periphery of said diaphragm between said casing and the body portion of said valve to form a 'pressure chamber in said casing, a plug engaging the body portion of said valve and holding said seat member intermediate the ends of said passage therein and opposite the end of a bore in the body portiono'f said .Valve which guides said ball valve member relativel to the port in said seat member, a thrust pin extending through said plug and guidedthereby into contactlwith and intermediate said diaphragm and said ball `valve'member with one cndthereof extending through the port in said seat member, a plunger, -a holder for guiding said plunger vklengthwise thereof and from which the ends offsaid plunger project, means for mounting said holder in the body portion of said valve with one end of said plunger opposite the side of said ball valvev member which is oppositeits side engaged by said thrust kpin and with lits other end projecting from the body por# tionof Lsaid valve,y means inksaid holder for biasing-said plunger into engagement with said ballk valve memberto resist the force applied thereto bysaid diaphragm acting through said thrust pin, means in said holder for adjusting the force of said biasingy means, means including parallel passages -for connecting said pressure chamber in said casing with a source of fluid whose'supply pressure is vsubject to change, means in one of said parallel passages yof saidpconnecting means for adjustably controlling the ratek aty which fluid passes throughfsaid one' parallel vpassage into and out of said pressure chamber in said casing,

and means in the `other of said parallelpassages of said connecting means for permitting the ow of huid through f said other parallel passage into said pressure chamber in saidcasing and yprohibiting the owr of said iluid therefrom, y

i i* -5 References Cited in the rile of this patent y y UNITED STATES PATENTS 2,510,207 Behnke et al.y June 6, 1950` 2,517,739 f Tyrner et al. Aug.f8, 1950 

1. IN A GAS-ARC SYSTEM ADAPTED TO BE SUPPLIED WITH SHIELDING GAS AND ELECTRIC WELDING CURRENT, AND COMPRISING A GAS-ARCH TORCH, A VALVE INTERPOSED IN THE CONDUIT THROUGH WHICH SAID SHIELDING GAS IS SUPPLIED TO SAID TORCH, AND A SWITCH INTERPOSED IN A CIRCUIT CONTROLLING THE FLOW OF ELECTRIC WELDING CURRENT TO SAID TORCH: APPARATUS FOR THE SEQUENTIAL CONTROL OF THE FLOW OF SAID SHIELDING GAS RELATIVE TO WELDING CURRENT FOR PROPER PRE-WELD AND POST-WELD GAS FLOW, COMPRISING A CONTROL FLUID CHAMBR, A CONTROL ELEMENT ASSOCAITED WITH SAID CONTROL FLUID CHAMBER WHICH IS DISPLACED IN A FORWARD DIRECTION UPON ADMISSION OF CONTROL FLUID UNDER PRESSURE TO SAID CONTROL FLUID CHAMBER AND WHICH IS DISPLACED IN THE REVERSE DIRECTION UPON DISCHARGE OF CONTROL FLUID FROM SAID CONTROL FLUID CHAMBER, MEANS RESPONSIVE TO THE DISPLACEMENT OF SAID CONTROL ELEMENT TO OPERATE SAID VALVE AND SAID SWITCH IN PRE-DETERMINED SEQUENCE IN A FORWARD DIRECTION AND IN A REVERSE SEQUENCE IN THE REVERSE DIRECTION AND METERING RATE MEANS FOR CONTROLLING AT DIFFERING RATES THE RESPECTIVE ADMISSION AND DISCHARGE OF CONTROL FLUID TO AND FROM SAID CHAMBER, TO THEREBY CAUSE A TIME DELAY PERIOD OF A DIFFERENT DURATION AS BETWEEN OPERATION OF SAID VALVE AND OPERATION OF SAID SWITCH IN THAT ORDER IN THEIR FORWARD DIRECTION, AND OPERATION OF SAID SWITCH AND OPERATION OF SAID VALVE IN THAT ORDER IN THE REVERSE DIRECTION. 